A system for sensing control in a toilet space is disclosed in Japanese Unexamined Patent Publication 2005-81032. In this system, a technique for sensing the motion of a to-be-sensed object by detecting the phase difference or number of waves using microwaves is combined with a technique for sensing the presence of the to-be-sensed object. The sensing range of such a human body sensing means is set so as to be able to sense a human body in a prescribed distance from the toilet.
However, the sensing range of the human body sensing means depends on the environment in which the human body sensing means is provided, such as temperature, and the size and shape of the toilet room. For instance, if the human body sensing means is concealed inside the toilet device, the attenuation amount of radio waves is changed by the state of the toilet device such as opening/closing of the toilet seat or toilet lid, and by the outer frame of equipment. This increases the variation of the sensing range. The sensing range may be set wider in view of the variation. However, this may result in also sensing a person having no intention of use (such as a person only passing in front of the toilet room).